fix: ensure deliverables directory is writable by container user (#116)

Pre-create the deliverables directory with proper permissions on the
host before starting containers, and surface permission errors instead
of silently swallowing them in save_deliverable.

shannon

@@ -194,6 +194,12 @@ cmd_start() {
   mkdir -p ./audit-logs
   chmod 777 ./audit-logs
 
+  # Ensure repo deliverables directory is writable by container user (UID 1001)
+  if [ -d "./repos/$REPO" ]; then
+    mkdir -p "./repos/$REPO/deliverables"
+    chmod 777 "./repos/$REPO/deliverables"
+  fi
+
   # Ensure containers are running (starts them if needed)
   ensure_containers